<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            
        }
        .page{
            /*  */
            padding:0 15px;
        }
        .header,.nav,.main,.footer{
            background-color: green;
            height: 100px;
            text-align: center;
            color: white;
            margin-bottom: 10px;
            line-height: 100px;
            border-radius: 10px;
        }
        .main{
            /* 
                两列式布局 
                启动了弹性布局 
                新的格式上下文，取代了原来的块级上下文
                页面排版 = 块级行内上下文(流体布局) + 布局格式上下文(flex， 响应式布局，......)
            */
            display: flex;
        }
        .article{
            flex:1;
            background-color: red;
        }
        :not(.footer){
            margin-bottom: 10px;
        }
        /* 右侧固定,左侧弹性分配空间的两列式布局方案 */
        .aside{
            width: 300px;
            background-color: pink;
        }
        .page>div:last-child{
            margin-bottom: 0;
        }
    </style>
</head>
<body>
    <!-- 传统写法 div+css 
        div 代表盒子  ?
    -->
    <div class="page">
        <div class="header">header</div>
        <div class="nav">nav</div>
        <div class="main">
            <div class="article">article</div>
            <div class="aside">aside</div>
        </div>
        <div class="footer">footer</div>
    </div>
</body>
</html>